Fire alarm signaling system



March s, 1940. P .HORNI 2,192,576

FIRE ALARM SIGNALING SYSTEM Filed Oct.. 20, 1957 Patented Mar. 5, 1940Unire STATES Claims.

Signaling systems such as those employed on nre alarm and likeinstallations, must necessarily have a great degree of reliability ofoperation to insure public safety and minimize the loss due y-5 todestruction of property by iire.

Faulty conditions which frequently arise in a re alarm signaling system,must be handled so that they are quickly corrected without materiallyaiecting the operation of the system or appreciably delaying rapid andcertain notication at nre headquarters of an alarm box which has beenactuated. v

Some of the signaling systems which are now in commercial use, not onlyutilize the normally 15 closed signaling loop energized by directcurrent,

but also employ an alternating current superimposed on the loop forsignaling bo-x location numbers and/or supervising the loop continuity.

To use a superimposed alternating current on a direct current energizedsignaling system, or vice versa, it is necessary to use coupling means,for example, ccndensers. While various signaling systems in thesignaling art show the use of a single condenser to couple thealternating curl `rent energy source with the direct current energizedsignaling loop to aord proper operation under a given set ofcircumstances, it is shown to be very old in the art to use twocondensers having one side of each condenserconnected to conductors ofopposite polarity and to have the opposite sides of the condensersuitably connected so that a point intermediate the two condensers maybe connected to a third conductor, such as a ground. An example of thistype of coupling is shown in the patent to Alfred Charles Brown,

Patent #1,181,427, issued May 2, 1916. The

Brown patent also shows the use of a single condenser.

Specically, reference may be had,Y for a more comprehensiveunderstanding of the present invention, to Figures 4 and 3,respectively, of the ,above-mentioned Brown patent, for a showing of theuse of two condensers and a single condenser.

The present invention has for an object, the

use of alternating current superimposed on a signaling system energizedby direct current, and

having a condenser coupling connecting one side of an alternatingcurrent source through a rectier to a condenser, and from the oppositeside ofthe condenser to the ground, which condenser may be cut out ofthe circuit to connect the one side of the rectier directly to theground in the event there is a failure of the alternating current energysource which is impressed upon the system, the-opposite side of thesecondaryof the l ing current.

energy source, which is shown in Figure 1, being connected to the loop.

The further object of the invention is to provide an alternating currentsource to be used in conjunction with a direct current signaling loop, 5wherein one side of the alternating current energy source is impressedon the signaling system at a mid-point of the battery to enable thesignaling system to have sub-stantially equal impressed voltages oneither side of the loop in the event y1()k vpresent inventionessentially as a unit.

Figure 2f indicates an open condition in the loop to show the varioussignaling paths primarily for the direct current. 25

Figures 3 and 4 are components of the diagram shown in Figure 2, and setforth the actual current paths of the components derived from thecircuit shown in Figure 2.

Referring particularly to Figure 1, we have a 30 signaling loop I, suchas several boxes or initiating stations: connected therein, which boxesare indicated as 2, 3, ll, 5, 6, and l. The box l is similar to the boxshown in Patent No. 1,528,596, which is of the type that has signalingcontact 35 sets 8 and 9, which are serially connected into the loop lfor the purpose of interrupting the signal- The contact lll isassociated with an armature ll which connects a point intermediate thetwo contact sets 8 and 5 to they@ ground or common return i2. The groundswitch is of the type that closes before or substantially simultaneouslywith the first opening of the contact sets 8 and 9, and ultimately opensbefore or substantially simultaneously with the nal clo- 45 sure of thecontact sets 8 and 9. The box 6 is merely representative of theconventional noninteriering transmitter which may be of the successiontype and is used in the present instance .to show the operation of thisbox in conjunction 50 with the present invention. An example of thistype of transmitter is presented in the copending application, SerialNo. 85,311, led June 15, V1936. Box l is merely representative of whatis commonly referred to `by those skilled in the art 55 as a bulldog boxwhile box 6 is merely representative of a non-interfering box. Bothboxes 1 and 6 are of the type which, under certain conditions, willcause a signal to be transmitted over an auxiliary circuit.

Box S has a contact set I3, which is infact a conventional box shunt,and connects terminals I4 and I5 together to complete the loop circuit,when the transmitter 6 is not in operation. Terminal I4 is connected toa contact set I6, which is in turn connected to one side of anon-interference magnet I8, the opposite side of said magnet I8 beingconnected to one side of a non-interference magnet I9, the opposite sideof which magnet I9 is connected to a contact set I1, which has one sidethereof connected to the terminal I5. It will, therefore, be seen thatwhen the contact set I3 is opened, a circuit may be traced from terminalI4 through the contact I6, noninterference magnet I8, non-intereferencemagnet I9, contact set I1, to the terminal I5, which shows that thenon-interference magnets are in series with the loop and that therevolving of the code wheel 29 by any conventional motor will permit thecode wheel follower 2| to drop down into the indentures on the codewheel and thereby cause opening and closing the contact sets I6 and I1in conformance with the indentures on the code wheel. The code wheel 2|in the box 1, likewise will, when caused to revolve by the operation ofthe box motor, permit the contact sets 8 and 9 to open and close inresponse to the irregular peripheral surface of the code wheel 2I.

Under normal conditions, it will be seen that a combined voltage of thebattery units 22 and 23 will be impressed upon the signaling loop atterminals 24 and 25'. Therefore, when the loop is closed, the currentwill iiow from the positive side of battery 22 to the terminal 24, overconductor 25, through register 26, over the conductor 21, through theboxes 2, 3, 6, 1, 5, and 4, through a conductor 28, through amanifestation means 29, a conductor 30, back to the negative side of thebattery 23, the positive side of said battery 23 being connected to thenegative side of battery 22.

It will, therefore, be seen that the voltage impressed upon the systemunder the closed loop will be the combined voltages of the batteries 22and 23. The manifestation device 29, which has just been referred to, isin series with the loop, and may have its armature 3| connected toeither contacts 32 or 33, which may be used as a control circuit forother devices such as line relays in the event the devices areelectrically connected with other signaling loops through repeaters ormay be connected to operate a manifestation device of the type shown as26 in Figure 4, which is shown as a register of the tape puncturingtype, which is responsive to signaling impulses initiated in atransmitter. Condensers 34 and 35 are connected respectively across theregister 26 and the magnet shown as 29. As has been previouslyexplained, the purpose of these Condensers is to permit the passage ofalternating current through said devices Without encountering theinductive effect of the devices 26 and 29. The primary of an alternatingcurrent transformer 36 is connected to an alternating current source,which primary feeds the secondary 31. A rectifier 45 is connected inseries with the secondary, and a condenser is connected to groundtherefrom, so that a circuit may be traced from the mid-point 38 betweentwo battery units, over a conductor 39, to a terminal 40, over thesecondary of the transformer 31, to a terminal 53, terminal 42, to therectifier. The opposite terminal 43 of the rectier 45 is connected toone side of a blocking condenser 44, the opposite side of said condenserbeing connected to a ground I2.

The alternating current impressed upon the rectifier 45 will have twoleads which connect from terminal 46 to a conductor 41, to one side of aregister 48, which is responsive to direct current, the opposite side ofsaid register being connected to a conductor 49, then to the terminal 58of the rectiiier 45.

It will, therefore, be seen that any actuation of the signaling contactsI6 and I1 in box 6, or signaling contacts 8 and 9 in box 1, will actuatethe register 26 and thereby communicate to headquarters any impulsesoriginated in the initiating stations. These impulses will also beimpressed upon the magnet 29 for the purpose of operating amanifestation means such as 58, in the event same were connected toterminals 3| and 32 of the manifestation device 29, as is shown inFigure 4.

The transmitter 1, in Figure 1, has a ground connection I2, which isconnected to the box during the operation of said transmitter, while thebox 6 is of the type which utilizes a ground connection and is connectedto said ground when contact 5I is engaged by the moving member 52,operable by any conventional mechanism. In this particular type oftransmitter, the contact set I3 which is in fact a box shunt, is openedbefore the signaling contacts start to operate. In the event the loop isclosed and the signal operates normally, the contact set 5I-52 will notbe closed. However, in the event of an abnormal opening in the line, themechanism, which may be of any conventional type, will cause the contactset 5I-52 to close for the purpose of signaling over the common returnor ground conductor I2.

However, for this to occur, it will be necessary to provide a signalingpath to the ground at the central oice, which path in the presentinvention is not provided unless there is a failure of the alternatingcurrent source, the reason for this being that it is not necessary inthe given case to signal with direct current over the ground as long asthere is alternating current provided for the system.

With the type 6 box and the loop normal, only the direct current signalwould be received on the register 26 and the manifestation device 29 forthe register 58, if same was connected as shown. However, in the type ofbox such as 1, both the registers 26 and the manifestation means 29, andalso the register 48 would be operated by each signaling impulse.

In the event of a shunted box, it will be seen that in both cases of thetypes of transmitters indicated, the direct current signal would not beable to get through. However, regarding the alternating current signal,it will be seen that in both the 6 and 1 types of transmitters, thealternating current signal would be able to get through to headquarters.

In Figure 1 it will be seen that a relay 54, responsive only toalternating current, is shown by the conventional symbol, and is inseries with a condenser C. The alternating current relay 54, and thecondenser which are in series, are connected across the terminals 40 and53 of the winding 31. This relay 54 is a supervisory relay for thelalternating current secondary and vsaid relay 54 is energized at alltimes when the normal alternating current is impressed on the system. Inthe event of failure of the alternating current source, the armature 55of the relay 54 will drop back to engage contact 56. lIt will,therefore, be seen that the condenser 44 which was connected fromterminal 43 of the rectifier to the ground I2, will now beshort-circuited by the contact set 55-53 to connect the terminal 43directly to the ground I2, thereby providing a path for the directcurrent, from the battery of the central oice vequipment to the groundI2.

For the purpose of explanation, Figure 2 is hereby shown as being moreclearly representative of the direct current circuit which would result,in the event the alternating current source fails and the relay 54permitted its contact set 53-55 to connect terminal 43 directly to theground I2, over the conductor 51. At X on Figure 2, between boxes 3 and5, we see the two ends of the loop L and L which represents the openends of the signaling conductor, which open in the loop interrupts thecontinuity of the normally closed signaling loop. With theabovementioned condition and the failure of the alternating currentpower, the manifestation devices and 23, respectively, would be operatedin response tothe initiating stations such as 2, 3, il, and 5, over aground connection. While these boxes which are shown in Figure 2 aremerely symbolic of an initiating station, it is to be understood thatthey may be of any suitable type and are not limited to a particulartype of transmitter.

Figures 3 and 4 are representative of the circuit components of Figure2, and show the opposite sides of a loop with their independent energysources as being independent signaling circuits, which they are in fact,even though certain of the conductors such as the ground and rectifierand its associated parts provide a cornmon path for the current flow. Itwill be seen that in both Figures 3 and 4, that the register 48 and partof the rectier and the secondary 31, are each common conductors for bothsides of the loop. In Figure 3 it will be noted that when a box ispulled such as that shown as Fig. 6, the transmitter will eventuallyconnect to the ground so that at least one of its signaling contactswill be able to interrupt the current flow and impulse the circuit forthe purpose of signaling its station identifying number. When thecircuit is closed through the ground switch such as contact set 5 I--52of 6, a circuit may be traced from the positive side of battery 22, overconductor` 25, through register 26, through conducto-r 21, through box2, box 3, and assuming box 3 is the station actuated, from the groundcontacts of the last-mentioned box to the common return or ground l2.The circuit may then be traced from the ground I2 which is connected tothe transmitter 3, to the ground I2 which is connected to the terminal43 of the rectifier 45, over the Z side of the rectiiier 45, throughconductor 41, through the register 48, over the conductor 49 to terminal5I), through the winding 31 of the transformer secondary 31, to terminal38, back to the negative side of the battery 22. Assuming that box 5 ispulled on the circuit shown in Fig. 4, a current path may be traced fromthe positive side of the battery 23, to terminal 38, through thetransformer secondary 31 through the Y side of the rectifier 45, throughconductor 41, register 48, conductor 49, through the Y' side of therectier, to terminal 43, back to ground I2,

through' the ground tothe lconnection in box 5, (such as contacts 5I and52 in Figure 1), which connects the ground tothe loop, over theconductor 28 to the manifestation means 29, through conductor 30 andback to the negative side of battery 23.v For the purpose ofexplanation, a register is shown as 58, and is connected to the contactsof the manifestation means 29 *so that at each impulse of the circuit, aregister will be operated.

A circuit may be traced from terminal 3|, through contact 32, over theconductor 59 to battery 60, conductor 6I, through the register 58 andback to the terminal 3|. In this case, the register will be operated ateach impulse and the station identifying number will be recorded thereonin response to the impulses of the signaling transmitter. While theregister 58 has been shown connected to operate in response to thecomponent of Figure 2 shown as Figure 4, it is clear -that the register48 may operate in response to any box on the loop under normalconditions since this register may have the characteristics which willpermit it to respond to half of the full Voltage impressed on the closedloop. 2

The register in itself, under normal conditions, responds to directcurrent since the alternating current which is the source of energy, isrectified to supply direct current for the register 48. It is to benoted that the direction of current flow through the register 48 is thesame in both components sho-wn in Figures 3 and 4 of Figure 2.

From the foregoing discussion, it is pointed out that the alternatingcurrent source may failand that in this event the coupling means wouldbe disconnected from the circuit by a` Contact set such as 55-55 so thatthe loop maybe metallically connected to ground.

While specic details of the system have been herein shown `anddescribed,'the invention vis not confined thereto as. changes andalterations may be and may become apparent to those skilled in the artwithout departing from the spirit thereof as defined by the appendedclaims.

Having thus described the invention, what I claim as new and desire tosecure by Letters Patent of the United States, is-

1. A signaling system comprising a normally closed signal loop energizedby direct current, a common conductor, transmitters in the loophavingmeans for opening and closing the signal loop and for connecting bothends of the loo-p at the transmitter to the common conductor, a windingconnected across said signal loop and said common conductor to providean alternating electromotive force therebetween, a coupling meanselectrically connected intermediate one side of said winding andsaidcommon conductor to prevent the passage of direct current,electro-magnetic means connected across said winding, and a circuitclosure means responsive to deenergization of said electromagnetic meansto shunt said coupling means to permit the passage of direct current.

2. A re alarm signaling system comprising a signal loop energized from adirect current source having an electrical mid-point terminal said loopincluding signal initiating stations capable of signal transmission oversaid loop, and said loop and a common return conductor, and a commonreturn therefor, a condenser, a rectifier having two input terminals andtwo output terminals, an alternating electromotive force source havingtwo terminals one of said terminals being connected to one of saidrectier input terminals, the other of said alternating electromotiveforce source ter- Vrninals being connected tothe electrical midpointterminal of the direct current source, the other of said rectifier inputterminals being connected to said common return conductor through saidcondenser, a signal receiver connected across said output terminals ofsaid rectier, and electromagnetic means shunting said alternatingelectromotive force source and responsive thereto capable of shortcircuiting said condenser upon failure of the alternating electromotiveforce source, to the end that in the event the alternating currentsource should fail and the loop continuity should become disrupted anysignal initiating stations operated on either side of the direct currentsource would actuate the signal receiver connected across the rectifieroutput terminals.

3. A fire alarm signaling system comprising a normally closed signalcircuit having signal transmitters therein for opening and closing thesignal current and for connecting both ends of said signal circuit to acommon return path, and a source of direct current energy therefor, acommon return path, a transformer having a secondary winding to impressan alternating electromotive force between said normally closed signalcircuit and said common return path, a blocking condenser seriallyconnected intermediate one side of said secondary and the common returnpath, means connected across said secondary and energized thereby, and anormally open contact set responsive to said last mentioned means havingone contact connected to the common return path and the other contactconnected to a point intermediate said secondary and said blockingcondenser, Whereby in the event the transformer secondary should becomedeenergized the contact set would close and short circuit said blockingcondenser.

4. A re alarm signaling system comprising a direct current energizedloop having signal transmitters connected therein for opening and clos--ing the loop Aand forV connecting both sides of said Aloop to a commonconductor, a common conductor, an energized transformer winding toimpress an alternating electromotive force between said loop andsaidcommon conductor, a coupling means to prevent the passage therethroughof direct current connected intermediate one side of said transformerwinding and the common conductor, means normally energized connectedacross said transformer winding, and means responsive to said lastmentioned means to connect the common conductor directly to a pointintermediate said transformer winding and said coupling means in theevent there would be an absence of the alternating electromotive forcein -said transformer Winding.

5. A signaling system comprising a normally closed signal loop energizedby direct current and including signal initiating stations capable ofsignal transmission over said loop, and said loop and a common returnconductor, and of connecting said signal initiating stations to a commonreturn conductor, a common return conductor, a rectier having input andoutput terminals, a condenser, an alternating electromotive force sourceserially connected to the input terminals of said rectifier, saidelectromotive force being impressed between the loop and the commonreturn conductor through said rectifier and said condenser, a signalreceiver connected to the output terminals of said rectifier forreceiving signal impulses from said initiating stations, andelectromagnetic responsive means connected across the electromotiveforce source to shunt the condenser and provide a signal conductingby-pass from the loop to the common return conductor in the event thealternating electromotive force should fail to maintain theelectromagnetic responsive means in an operative condition.

PAUL P. HORNI.

